42090731 has 2 divisors, whose sum is σ = 42090732. Its totient is φ = 42090730.

The previous prime is 42090707. The next prime is 42090733. The reversal of 42090731 is 13709024.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 42090731 - 2¹⁸ = 41828587 is a prime.

It is a super-2 number, since 2×42090731² = 3543259272228722, which contains 22 as substring.

Together with 42090733, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 42090731.

It is not a weakly prime, because it can be changed into another prime (42090733) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21045365 + 21045366.

It is an arithmetic number, because the mean of its divisors is an integer number (21045366).

Almost surely, 2^42090731 is an apocalyptic number.

42090731 is a deficient number, since it is larger than the sum of its proper divisors (1).

42090731 is an equidigital number, since it uses as much as digits as its factorization.

42090731 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 42090731 is about 6487.7369706239. The cubic root of 42090731 is about 347.8527887284.

Adding to 42090731 its reverse (13709024), we get a palindrome (55799755).

The spelling of 42090731 in words is "forty-two million, ninety thousand, seven hundred thirty-one".